1. Field of the Invention
This invention relates to integral plastic fasteners, especially for plastic covers to be attached to seat belt retractors.
2. Description of the Prior Art
Devices such as covers for rewind springs and for tension relieving mechanisms have been attached to seat belt retractors by a variety of means. Such means include the use of integral plastic fasteners. For example, plastic push pin-type fasteners have been molded into retractor spring covers. In addition, split pin-type fasteners have been suggested, as disclosed in U.S. Pat. No. 4,204,652 to Cislak et al., for example. Furthermore, integral plastic fasteners for retractor spring covers have been utilized which include outwardly tapered legs.
The prior fasteners, although generally acceptable, are either difficult (and hence relatively expensive) to mold or have extraction strengths which are only moderately high. It would be desirable to provide an integral fastener which was easy to mold and yet offered high extraction strengths.
Cofiled, commonly assigned application of J. M. Cachia, J. M. Lentz and D. M. Lynch entitled "Integral Plastic Fastener" discloses such a fastener which has a hollow core of circular cross-section. It has been found that improved results are obtained with cores of different shapes.